1. Field of the Invention
This invention relates to froth flotation cells. More particularly, this invention relates to froth flotation cells utilized for removing mineral values from ore slurries. This invention provides froth flotation cells wherein greater collection surface area is provided through a network of launders to enhance the efficiency of froth collection. This invention also relates to an associated froth launder assembly and to a method for assembling a froth flotation cell.
2. Background of Prior Art
Froth flotation cells are used to separate mineral values from mineral wastes. An ore is finely ground and suspended as a water-based slurry or pulp in a flotation cell. An impeller or rotor is turned at a high speed in the slurry to suspend the mineral particulates and to distribute or disperse air bubbles into the slurry. The mineral values attach to the air bubbles. The bubbles with the entrained mineral values then rise to form a froth atop the pulp or slurry pool. The froth overflows a weir and is collected in a launder for further processing. Examples of flotation cells are described in U.S. Pat. No. 5,611,917 to Degner, U.S. Pat. No. 4,737,272 to Szatkowski et al., U.S. Pat. No. 3,993,563 to Degner, U.S. Pat. No. 5,219,467 to Nyman et al., U.S. Pat. No. 5,251,764 to Nitti et al., and U.S. Pat. No. 5,039,400 to Kallioninen et al. In the flotation machines of some of these references, air is supplied to the pulp or slurry via a separate pumping mechanism.
Commercially available flotation cells usually include a launder along the periphery of the flotation cell tank. Such cells are limited in their froth removal capabilities as the froth must travel to the periphery of the tank before being collected by the launder. It is therefore desirable to provide a more efficient manner of removing the froth from the tank.
During flotation cell operation, the rotation of the impeller imparts rotational energy to the pulp or slurry pool. This rotational energy is transferred to the froth phase, which develops angular velocity in the slurry. This angular velocity increases the time to remove the froth and can cause the mineral values to drop back into the pulp phase, thus reducing the efficiency of the flotation cell. Reducing the angular velocity and increasing the radial velocity of the fluid mass in the tank can increase the overall effectiveness of the flotation cell. U.S. application Ser. No. 08/920,800 assigned to the assignee of this application discloses an apparatus and method for reducing the angular velocity of the pulp slurry through the use of radially disposed baffle plates. U.S. application Ser. No. 08/920,800 is incorporated herein by reference.
The present invention addresses the above-noted deficiencies and provides flotation cells with a network of launders that removes froth from throughout the tank. Additionally, baffle plates are provided in the tank to reduce the angular velocity of the slurry, thereby increasing the efficiency of the flotation cell.